If you've spent any time stalking Hollywood's hottest starlets on Instagram lately, then chances are you've seen videos of their intense workouts with MackFit, the trainer everyone is dying to work with. His long list of clients includes some of our top #BodyGoals, like Modern Family star Ariel Winter, YouTuber Hannah Stocking, influencer Liane V, and Kylie Jenner besties Stassi Karanikolaou and Jordyn Woods. Now, the in-demand trainer is chatting exclusively with Life & Style about his rise to the top, fitness tips, and how social media is changing the game.

"I think with social media it's easier than ever to be inspired, since all of the models and celebrities that you look up to are on Instagram," Mack explains. "The internet is an incredible tool to educate everyone on fitness." Personally, we're obsessed with watching stars tone their abs with his MackFit Core Sliders, but don't worry, those Instagram Stories aren't distracting them from getting the job done. "When we post videos, they post on their last set," Mack insists. "If they don't get it right, they have to do it again, so they're really doing extra sets because they want to post it on Instagram." The tip is a helpful motivator to make sure the end of your workout is just as perfect as the beginning!

Another important fitness hack (though not necessarily new) is to train with a buddy. "I don't train one-on-one, I train one-on-two," says Mack. "I pair clients based on training levels and experience. They go together, they push each other, they motivate each other. All of my training is based off of that." Mack says that some of his clients have even become good friends thanks to him!

Not everyone can get to LA to train with Mack, but luckily he's willing to share how you can get the same results on your own. "Consistency is everything, it's key," he says. "My clients work out at least three times a week, then I also have them doing cardio on their own. I have a ten-mile requirement." Mack says his clients need to do ten miles of cardio, switching between things like hiking, treadmill, and Stairmaster so they confuse their muscles and don't plateau. He also requires that clients do his three to four minute MackFit Ab Cycle every single day, which includes one set of six workouts. As for the days in the gym? He likes to start with static and active stretching, five minutes of warm-up cardio, and then resistance, plyo, or weight training. That's the part we get to see stars post on Instagram.

Mack doesn't subscribe to the idea that fitness is 20% exercise and 80% diet. "I think you need to go all in, 100% on both," he explains. "My clients will eat clean for the whole week and then go in on the weekend. During the week, when they're training with me, they're eating clean." He gives clients the weekend to enjoy themselves because he wants the program to be something they can maintain forever. "A lot of these diets, they're so strict. Of course they're going to work. But how long can you do that? You're starving yourself, it's not a lifestyle change." Instead, Mack pushes patience. "My clients know that it's not going to come overnight, we just do this on a daily, weekly, monthly basis and then the results will come."

He urges clients not to focus on the scale for these results, either. "[One client] was so focused on the scale. After three months she's like 'Hey, I only lost two pounds.' So I covered the scale and showed her before and after pictures. She was shocked because it was a drastic change. Her waist was smaller, her legs were thinner, she built muscle, you have to stop looking at the scale and focus on how you look, how you feel. Her mindset completely changed after that."

It may seem like Mack came out of nowhere, but he's been busting his butt behind the scenes for nearly a decade to become Hollywood (and Instagram)'s most sought-after trainer. He began training part-time while working three other jobs, and finally started his own company four years ago. After snagging his first influencer client, word began spreading that he's the guy to kick your workouts into high gear. He went on to work with big names like Tess Holliday, and now he "hasn't handed out a business card in years" because people come to him.

Mack thinks his unique attitude and sensitivity to clients' needs is what makes him so successful. "One has the paparazzi that follow her around," he explains. "She needs someone that knows how to handle that. I try to take her into the gym so no pictures are taken, it takes someone that understands the lifestyle and doesn't let it get to their head, which I never do." He's also not intimidated by his clients or their fame, saying, "If I feel like you're off your game, I'm going to tell you. I have thirty clients, I'm not going to be your yes-man."

Mack's success has been a dream come true, and he couldn't be happier. "The physical part of it has always been great for me, but I've always loved helping people change their lives. Inspiring people, motivating people — physically but also mentally as well," he says. "I love helping people, being a trainer just fell in my lap."